Transports: fix ok_codes getter for empty list

Bug: T167394
Change-Id: Ifaac41881c7c34e88d0240ac207525c9d8879604

cumin/tests/unit/transports/test_init.py

@@ -150,6 +150,11 @@ def test_timeout_setter(self):
 
     def test_ok_codes_getter(self):
         """Should return the ok_codes set, [0] otherwise."""
+        # Test empty list
+        command = transports.Command('command1')
+        command.ok_codes = []
+        self.assertListEqual(command.ok_codes, [])
+
         for command in self.commands:
             self.assertListEqual(command['obj'].ok_codes, command.get('ok_codes', [0]))
 
@@ -168,16 +173,20 @@ def test_ok_codes_setter(self):
         command.ok_codes = None
         self.assertIsNone(command._ok_codes)
 
+        command.ok_codes = []
+        self.assertListEqual(command._ok_codes, [])
+
         with self.assertRaisesRegexp(transports.WorkerError, r'ok_codes must be a list or None'):
             command.ok_codes = 'invalid_value'
 
+        message_regex = r'must be a list of integers in the range'
         for i in (-1, 0.0, 100.0, 256, 'invalid_value'):
             codes = [i]
-            with self.assertRaisesRegexp(transports.WorkerError, r'must be a list of integers in the range'):
+            with self.assertRaisesRegexp(transports.WorkerError, message_regex):
                 command.ok_codes = codes
 
             codes.insert(0, 0)
-            with self.assertRaisesRegexp(transports.WorkerError, r'must be a list of integers in the range'):
+            with self.assertRaisesRegexp(transports.WorkerError, message_regex):
                 command.ok_codes = codes
 
 

cumin/transports/__init__.py

@@ -106,16 +106,20 @@ def timeout(self, value):
     @property
     def ok_codes(self):
         """Getter for the command's ok_codes property, return a list with only the element 0 if not set."""
-        return self._ok_codes or [0]
+        ok_codes = self._ok_codes
+        if ok_codes is None:
+            ok_codes = [0]
+
+        return ok_codes
 
     @ok_codes.setter
     def ok_codes(self, value):
         """Setter for the command's ok_codes property with validation, raise WorkerError if not valid.
 
         Arguments:
-        value -- the command's list of exit codes to be considered successful for the execution. Must be a list integers
-                 in the range 0-255 or None to unset it. The exit code 0 is considered successful by default, it can be
-                 overriden setting this property.
+        value -- the command's list of exit codes to be considered successful for the execution. Must be a list of
+                 integers in the range 0-255 or None to unset it. The exit code 0 is considered successful by default,
+                 but it can be overriden setting this property. An empty list is also accepted.
         """
         if value is None:
             self._ok_codes = value